<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>加载动画</title>
    <style>
      * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
      }
      body {
        min-height: 100vh;
        display: flex;
        justify-content: center;
        align-items: center;
        background-color: #000c18;
      }
      .loader {
        width: 50px;
        height: 50px;
        border-radius: 50%;
        display: inline-block;
        position: relative;
        border: 10px solid;
        box-sizing: border-box;
        animation: rotating 0.7s linear infinite;
      }
      @keyframes rotating {
        0% {
          border-color: rgba(255, 255, 255, 0) rgba(255, 255, 255, 0) rgba(255, 255, 255, 0) rgba(255, 255, 255, 0);
        }
        25% {
          border-color: #ffff00 rgba(255, 255, 255, 0) rgba(255, 255, 255, 0) rgba(255, 255, 255, 0);
        }
        50% {
          border-color: #ffff00 #ffff00 rgba(255, 255, 255, 0) rgba(255, 255, 255, 0);
        }
        75% {
          border-color: #ffff00 #ffff00 #ffff00 rgba(255, 255, 255, 0);
        }
        100% {
          border-color: #ffff00 #ffff00 #ffff00 #ffff00;
        }
      }
    </style>
  </head>
  <body>
    <span class="loader"></span>
  </body>
</html>
